Writing a Mac application in GTK is, again, not conducive to the goal of learning to program a new platform. Wrappers such as GTK around native objC, Cocoa, and Swift are a distraction from the main purpose of learning those things.
No, I didn't mean to GTK, but for Carbon or whatever API Mac OS used.
The game is already on GTK and JS, so it would be easily portable
as they are really simple games (they have even an Android port).